A. Field of the Disclosure
This relates to fluid delivery systems, and more particularly, to a fluid delivery system such as a ball tube connecting a high-pressure oil rail to a diesel fuel injector featuring deflection features to deflect leaked fluids.
B. Background
The fuel injector system used on a 6.0L diesel or VT365 class engine, for example, features a ball tube as a pivotable hydraulic union between a high-pressure oil rail and the fuel injectors. This example ball tube accommodates motion between the oil rail and the fuel injector in three dimensions. It features a wide-diameter ball end connected to the oil rail and has a narrower diameter at the fuel injector end. The oil delivered by the ball tube provides the hydraulic force necessary for the fuel injector to atomize diesel fuel for combustion.
Over time, exposure to oil, heat and high pressures at the ball end of the tube cause the seal on that end to harden, reducing the seal's efficacy and causing leaks. These leaks allow high-pressure oil to reach the seal at the injector end via fluid dynamics along the smooth outer surface of the ball tube. When these leaks reach the other end of the ball tube, the high-pressure oil abrasively wears away at the fuel injector seal in a manner similar to a sand blaster. This failure mode removes material from the seal at the fuel injector end, which leads to a bigger leak than one caused by a hardened seal, which is the common failure mode for the seal at the oil rail end of the ball tube. Eventually, the leak becomes large enough to decrease the oil pressure to the point where the oil cannot hydraulically drive the fuel injector. The oil can cease to drive the fuel injector either because the engine PCM senses inadequate oil pressure to fire the injectors and does not command the fuel injectors to open or simply because the oil pressure is too low for the system to function, even with the fuel injectors opened. This failure results in a no start situation, putting the vehicle in a non-running condition. Thus, there is a need in the field of diesel engines, and more particularly the field of fuel injectors, for a fluid delivery system that prevents the hydrodynamic flow of fluids along the outside of the delivery mechanism.